I use Paypal to collect deposits for my studio headshot sessions. It's very convenient, and since my local post office seems to lose about half of my mail, checks are not really an option.
If you don't have a Paypal account, don't worry, you can still use the service to send your deposit using your credit or debit card, as the photos here illustrate. I will send you an email via Paypal requesting the deposit. You can see a screenshot of that email above.
Next just click on the link in the email. On the webpage that opens, go to the bottom and click on "Pay as a Guest." After that you just enter your credit card info and you're done!